This invention relates to focused charged ion-beam apparatus. Its sample processing and its observation method for the above apparatus, which can observe the sample surface by way of detecting the secondary particles which in emitted (generated) from the said sample through the irradiation of the focused ion-beam, and which can process a transmitted area of the sample surface by way of ion-beam etching and ion-beam CVD processing, by way of which thin-film processing of the sample and the estimation of its thickness can be realized, and especially the processing of the most suitable thickness and this shape can be simply realized in TEM sample processing.
Traditional focused ion-beam apparatus in prior art is, as disclosed in Japanese official gazette under the volume of Unexamined Published Japanese Patent Application 59-168652, that which derives its ion-beam from the liquid metal ion source through the electrode, transform the ion beam above to the focused one by way of the aperture and the electrostatic lens and deflects and scans the focused ion-beam by way that the focused ion-beam irradiates a predetermined area of the sample surface through deflecting electrode.
Due to the repeated irradiation of the said scanned focused ion-beam on the sample surface 4, a predetermined area on the sample surface 4 are come off since it is spattered by ion-beam. And an ion-beam CVD metal film can be formed on the focused ion-beam irradiation area on the sample 4 by way of blasting through nozzle of the gas gun for deposit. These functions are utilized in the circuit amendment (correction) and/or process appreciation, of sample IC. By way of this utilization above, debug time in IC development. (Refer to "Monthly Semiconductor World", Vol. 1987.9.]
Recently, a case is reported that sample making of TEM cross-section is done by focused ion-beam apparatus and its observation result of cross-section TEM area on sample surface is also reported (The 37th Applied Physics Society 1990.3 "How to make (process) TEM Cross-section Sample by Focused Ion-beam"). According to this method, cross-section TEM (transmission electron microscope) sample making at a predetermined area can be done in short time compared to the traditional ion-milling method.
An embodiment of traditional focused ion-beam apparatus in prior art is shown in FIG. 3. Liquid metal ion source is used as for ion source 1. The ion-beam 2 which is derived from the ion source 1 irradiates the sample surface 4 by way of focused and scanned by ion optics systems 3. The ion-optics systems 3 is comprising of an aperture 30 which passes only optical axis of ion-beam 2 through, an electrostatic lens 31 which focuses ion-beam 2, a deflecting electrode 32 which deflects the optical axis 2 of focused ion-beam for the purpose of irradiation of the focused ion-beam on a predetermined area on the sample surface 4, a blanker 33 which controls on-off of irradiation of focused ion-beam 2 on sample surface 4, and etc.
The focused ion-beam 2 etches the sample surface 4 and discharges the secondary particle which is excited by ion-beam. The secondary electron in these secondary particle is detected by the secondary electron detector and is displayed on observation CRT which is not shown in the Figure, as SIM image. And at the same time with irradiation of ion-beam 2, CVD gas is supplied through the nozzle of gas gun 4, and therefore a thin-film is formed on the sample surface 4. This kind of ion-beam processing apparatus is traditionally utilized for cutting off or connection, processing of cross-section surface, or observation, of IC circuits.
When cross-section surface sample for TEM is made by way of apparatus in prior art above, the front and rear sides of observation area on the sample which is sliced mechanically towards several (some) 10 .mu.m is removed through ion-beam etching, in order that a "wall" less than 0.5 .mu.m in thickness is left. Next, observation of the processed shape or confirmation of cross-section surface of sample through image observation by scanning electron microscope (hereinunder abbreviated as SEM) in order to avoid the damage due to ion-beam irradiation and if necessary, processing is continued. Then the observation of after-process sample is made by TEM and ion-beam etching may be necessitated again in case that the processing above is not sufficient to observation. This method above takes much time for preparation of vacuous atmosphere or for sample position adjustment, etc., since a sample is put into and picked out of, several vacuum utilization devices, and has the difficulty in processing of the optimal cross-section surface of TEM sample.